The anatomical and functional organization of the second somatosensory cortex (SII) is not as clear as that of the primary somatosensory cortex (SI) in the rat. The proposed research has the following aims: 1) to study the corticocortical connections between the face areas of SII and SI in the adult rat; 2) to determine the topography of cholinergic projections from the nucleus basalis of Meynert to the face area of SII in the rat; 3) to determine if metabolic activity reduced in the representation of row D whiskers in SII of the adult rat after clipping whiskers in row D and leaving the other whiskers intact; and 4) to provide research experiences to two undergraduate students at Rust College. Retrograde and anterograde tracers will be injected into the face area of SI and retrograde tracers will be injected into SII. Choline acetyltransferase immunocytochemistry will be done to determine the percentage of neurons in the nucleus basalis of Meynert that project to the SII face area that are cholinergic. Cytochrome oxidase histochemistry will be done to detect any metabolic activity changes. An understanding of the organization of the corticocortical connections of SII and activity in SII may be important for processing sensory information and shaping cortical maps.